1. Field of the Invention
The present invention relates to a passenger airbag system, more particularly a passenger airbag system in which the portion of an airbag cushion which contacts the head of the occupant in a child restraint system mounted on the passenger seat is depressed when the airbag cushion inflates.
2. Description of the Related Art
In general, vehicles are equipped with airbag systems that prevent passengers from being hurt by direct impact against the structure of the vehicle by inflating between the structure of the vehicle and the passengers in a collision.
The airbag systems are operated by an ACU (Airbag Control Unit) that controls an inflator, which is a gas generator, in response to a signal detected by a sensor that senses a collision. That is, as the gas-generating substance inside the inflator is exploded by a control command from the ACU and gas is generated, the gas flows into the airbag cushion connected to the inflator and the airbag cushion is inflated by the gas flowing inside, thereby protecting the passenger.
The airbag cushions, however, are generally manufactured to be expanded by expansion pressure for protecting adults, in consideration of the body conditions of adults. However, in some cases, not only adults, but infants or children sit in the passenger seat, the excessive expansion pressure of the passenger airbag cushion is potentially a dangerous life threatening factor for of the infants or children.
In practice, North America has established a law to preclude infants and children from being hurt due to excessive expansion pressure of the passenger airbag cushion, by classifying the passengers in the passenger seat, which are infants to 1 year or under and 3 years or under, and children 6 years or under.
Therefore, there have been conducted many researches for developing passenger airbag cushions for protecting all passengers, that is, infants 1 year or under, 3 years or under, and children 6 years or under, in addition to adults, by controlling the expansion pressure of the passenger airbag cushion.